The 20th century saw several efforts to prove that acquired traits could be inherited, most ending in disappointment, pseudoscience, or even tragedy.
August Weismann, a founder of germ cell biology, tested this by cutting off the tails of mice for 19 generations. Yet, every new generation was born with a tail. Acquired changes (in this case, tail loss) were not inherited.
Trofim Lysenko, a Soviet agriculturalist, promoted Lamarckian ideas and persecuted geneticists who opposed him. His policies contributed to catastrophic famines.
Paul Kammerer falsely claimed to show inherited changes in frogs, but his work was exposed as fraudulent, and he tragically took his own life.
James McConnell claimed that memories in planaria (flatworms) could be transferred by feeding one worm to another, a claim that was never substantiated and is now considered pseudoscientific.
This dark history underscores the importance of rigor and skepticism in scientific inquiry. And yet, with modern tools and knowledge, the question still beckons: can acquired traits be inherited? This is where enters the scene.
Revisiting the Question: Can Acquired Traits Be Inherited?
To explore this, we turned to a tiny nematode called Caenorhabditis elegans (C. elegans). This unassuming roundworm is ideal for genetic research:
It is a hermaphrodite, capable of producing genetically identical offspring.
It has a short generation time of just three days, allowing researchers to observe many generations quickly.
Every C. elegans, and indeed every human, has roughly 20,000 genes. These genes are read by an enzyme called RNA polymerase, which copies DNA into RNA, eventually producing proteins, the molecules that do most of the work in our cells.
Here's a critical detail: while every cell in your body contains the same DNA, only a subset of genes is active (or "on") in each cell type. That's why skin cells, neurons, and liver cells behave differently, they express different genes.